Hello,
Although I doubt it will really make it into Python's grammar, I am
all +1 for the idea of having "repeat" as a loop keyword in Python.
Actually, I have been using "repeat" as a keyword in Python for quite
some time now, and found it not only convenient, but also a great help
in education.
My version of "repeat" has two versions. The primary usage is with an
expression that evaluates to a number and specifies how many times the
loop is to be repeated:
```
repeat <INT>:
<SUITE>
```
The second version is without the number, and, indeed, stands for an
infinite loop.
```
repeat:
<SUITE>
```
I must admit, though, that I had hardly ever reason to use the second form.
The implementation is currently built on top of Jython, and uses
something like a preprocessor to implement the "repeat"-keyword. In
order to keep some backward compatibility, the preprocessor does check
a few cases to determine how it is used, and does not always treat it
as a keyword.
Even though it is possible to write a parser that detects if "repeat"
is used as the keyword for a loop or anything else, it will make the
syntax very brittle. Take, for instance:
```
repeat (3*4)
```
Now, is this supposed to be a function call, or is it a
`repeat`-statement with a missing colon at the end?
I therefore would strongly advise against having a word act as a
keyword sometimes, and sometimes not. Probably a better solution
would be to have something like `from __features__ import repeat` at
the beginning.
My reason for introducing "repeat" into Python in the first place was
because of didactical considerations. Even though it might not seem
so, variables are indeed a very hard concept in programming,
particularly for younger students. And variables get particularly
hard when combined with loops, where the value of a variable changes
all the time (this requires a lot of abstract thinking to be properly
understood). Loops alone, on the other hand, are a relatively easy
concept that could be used early one. So, there is this dilemma: how
do you teach loops at an early stage without using variables? That's
when I added the "repeat"-keyword for loops, and it has worked
marvellously so far :).
Cheers,
Tobias
Quoting James Lu <jam...@gmail.com>:
repeat could be only considered a keyword when it’s used as a loop
Sent from my iPhone
On Sep 26, 2018, at 8:46 AM, Brice Parent <cont...@brice.xyz> wrote:
Le 26/09/2018 à 14:33, James Lu a écrit :
what about “repeat:”?
Sent from my iPhone
I'm not sure it was on purpose, but you replied to me only, and not
the entire list.
I believe the adding of a new keyword to do something that is
already straightforward (`while True:`), and that doesn't add any
new functionality, won't probably ever be accepted.
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